Contact-spring.



H. A. WALLACE,

CONTACT SPRING.

APPLICATION FILED AUG.2I. 1914. RENEWED JULY 13. ms.

Patented'Apr. 16, 1918.

FEG.2

INVENTOR FIG.6

WITNESSES HERBERT A. WALL CE;orrrrrsBURGn, rmvlvsxn enm, nssrelto swrron & SIGNAL COMPANY, or swIssvALE;jPEnNsYLvAnm A.

' PENNSYLVANIA.

f To all whom it may concern.

. Be it known that ahitian:

a citizen of the United States, residing at Pittsburgh, in the county. of Allegheny and State of Pennsylvania have invented cer tain new and useful Improvements in Con- I tact-Springs, of which the. following is a specification. g My invention relates to contact springs.

One object of myinvention is to provide a contact spring which isrigid in the plane of movement .of the springv so that it can exert considerablecontact pressure without bending, but which iseasily distorted by torsional stress so vthatthe,contacting edgezk and 11, attached thereto are prefer-ably,-

of the spring can readily aline itself with the-surface of-thefixed contact block.

' cation to a relay,

Another object of my. invention is the con.- strnction of a contact springof the abovedescribedcharacter from aflsingle piece of material. i

I will describe. one form of contact spring,

embodying my invention, showing its appliand explaln one methodof making the said spring,- and will their point out the novel features thereof in claims.

In the accompanying drawings, Figure 1 is a view showing a portion-0f a relay having applied thereto one form of contact spring embodying my invention. Fig. 2 is a top view on an enlargediscale showing the contact spring shown in Fig. 1. Fig. 3 is a bottom view on an'enlarged scale showmg the same contact spri'ng' and showing a for attaching it to the armature of.

means the relay. Fig. I is a perspective view showing more clearly the construction of the contactspring shown in the preceding views. Fig. 5 is a plan and Fig. 6 a side elevation of a blank from which the Contact spring is formed.

Referring to Fig. 1, the relay here shown comprises an electromagnet 1 mounted on a top plate 2 z llld comprising a core 3 which passes through the top plate 2 and to the lower end of which is secured a soft iron polepiece l. An armatureh carryingtwo studs 7 of insulating material such as bone, is pivoted at point 6 and is adapted to be attracted by the pole-piece l of the electromagnet when the latter is energized. As shown in Figs. 1 and 3, each stud is provided with a vertical saw cut through which passes a contact spring 8, which spring is secured to, the studs by means of pins 9 Specification ofiLeltte Application filed Augustzj ilgl i Serial No. 858,9 4

l which is attached is likewise mounted in top plate 2 by nuts 20.

describe. I first punch the tongue 11 on the conzeoanrron or .S Patentm o with fixed contacts "or .13 l

the electromagnet 1 is energize gized. here shown a block of graphite mounted in '60 The fixed contact 12'compris'es. as

a jaw formed in the head of a screw 17 which passes up through the-plate 2"and is attached thereto by nuts 16. The fixed contact 13 comprises a block of"electifo-con'- ductive material fixed on a brass strip" 18 to a screw 19, wliichtscrew The contact spring 8 and managers 10 though not necessarily, formed from a single piece of sheet metal and may,'for exaniple, be. made in the manner which I will now from' a piece of sheet metal a blank of substantially the shape and proportions shownin Fig.1.), at the-same time punching a tongue 11 as shown? more clearly in Fig. 6 (in order to clearly illustrate the structure the thickness of the sheet metal is greatly exaggerated'in proportion to the other dimensionsin Fig. 6). Ithen bend line 11? to the position shown in Figs. 1 and 4;, so that its edge 11 may make 'and break contact with the fixed contact member 13 of Fig. 1. I then fold the right-hand part of the blank on the line 21, at the same time grasping the left- -hand end as far as lines 10 and bending it slightly upward to form the contact finger 10, the edge 10 of which mal't'es and breaks eontact with the fixed contact member 12 of Fig. 1. The holes .9 may then be formed in the folded portion of the spring to accommodate the pins 9 by which the spring is attached to the relay armature.

Of course, if theback contact finger is'not. needed, as is sometimes the case, the tongue 11 would not be formed in punching the blank, but the operation would otherwise be the sameas I have-just describe'd.-

It will be seen that the plane of the body of spring 8 is parallel to 'thedirection of movement of the spring caused by relay armature 5, so that the spring resists bending in this direction; eonsiderable force can therefore be exerted on the spring by the relaymrrnatnre, thus securing considerable pressure of thefinger .10 on block 12 and thereby insuring good electrical contact be;

' able bending of the spring 8 in the vertical armature is attracted by pole-piece tween. these two members, without apprecidirection. The spring yields readily,-however, to torsional stresses, so that it can readily twist toaline the contacting edge 10 against the contact block 12. Thus wherti 4k, 1 one end of edge 10 strikes block 12, the finger 8 will readily twist, due to the force exerted thereon by armature 5, and so will cause the entire length of edge 10 to make contact with block 1:2.

v Although I have shown and described only'one form of contact spring embodying my invention, it is understood that various changes and -modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. The process of making a contact spring [out of an elongated flat blank of sheet metal which consists in folding said blank longitudinally upward throughout one portion and simultaneously bending the remaining fiat portion of the blank upward.-

2. The process of making a contact spring having an upper and a lower contact finger out of an elongated fiat blank of sheet metal which consists in cutting a tongue in said blank, bending said tongue downward to form one, contact finger, then folding the blank longitudinally upward throughout that portion of the blank which extends from one end of said blank to the root of said tongue and simultaneously bending the remaining flat portion of the blank upward to form the upper contact finger.

3. A contact spring formed out of a single strip of flexible material one portion of said strip being flat to form a straight contacting edge, and another portion of said strip being folded lengthwise upon itself to form a lever portion.

4-. A contact spring adapted for movement in one plane and comprising a single strip of flexible material, one portion of said strip being flat to form a straight contacting edge at right angles to said plane of movement, and another portion of said strip being folded longitudinally in said plane of movement to form a lever arm which yields readily to torsional strain but resists bending in the said plane of movement.

5. .A contact spring formed out of a single strip of flexible material and comprising a lever arm portion wherein said strip is folded'longitudinally upward, a lower con tact finger formed of a tongue out out of said strip and bent downwardly from said lever arm portion, and an upper contactv finger formed out of the remaining portion of said strip and bent upwardly from said lever arm. i

6. A contact spring having a. thin fiat body portion capable of yielding readily un- HERBERT A. WALLACE.

Witnesses:

' A. H'ERMAN VVEGNER, EDWARD MoGoUGH.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. (2. 

